SAUGERTIES — Police said a Montgomery man suffered arm and back injuries Friday when he was hit by a 43-foot tractor-trailer while directing truck traffic.Saugerties police said Keith Muller, 57, was directing two tractor-trailers at the corner of Main Street and Washington Avenue when he was struck by one of them.According to police, Muller said he had waved one tractor-trailer through the intersection, and, believing it had completely passed his location, began to walk backward on Main Street as he started to wave the tractor-trailer on from Washington Avenue. But police said, the first tractor-trailer had not completely passed. Muller's arm got caught and he was flipped around into the trailer portion of the passing truck.Witnesses said Muller was wearing a safety vest and helmet when he was struck.Richard J. Bayne